Island



(No Model.)

E. DUFFY.

PLUMB LEVEL.

180.860,378. Patented Ma,1-.29, 1887.

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UNITED STATES PATENT OFFICE.

EDVARD DUFFY, OF PAVVTUCKET, RHODE ISLAND.

PLUMB-LEVEL.

SPECIFICATION forming part of Letters Patent No. 360,378, dated March 29, 1887.

Application filed November 8, 1888. SeralNo. 218,227. (No model.)

To ctZZ whom t may concern:

Be it known that I, EDWARD DUFFY, of the city or" Pawtucket, in the county of Providence and State of Rhode Island, have invented certain new and useful Improvements in Gravity-Levels, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming part of this specification.

This invention relates to a device or level for ascertaining the relative inclination or angie of 'a certain line 0r surface to a horizontal i plane.

As is well known, the ordinary spirit and plumb-line levels are awkward to use in some cases, and in many cases they are not suited for the work of iinding certain angles and leveling. In this class of devices it is desirable to have a level that will be universally adaptable and suited to find a level or horii zontal line and the angularity of any line or surface to a horizontal plane, and that may be readily used in inconvenient situations, and that may have the indicating or registering hand set or ixed at the position registered for subsequent reading and calculation.

The objects of my invention are to provide a form of gravity-ievel that will be handy and iitted for allrequired work in ascertaining the relative inclination of any lines and surfaces to the horizontal plane, and that can be set at the registering-points for subsequent reading.

To the aforesaid purposes my invention consists, chiefly, in the employment of a pendulum-bar pivoted near the center thereof and of a dial having the degrees of a'circle marked thereon for the pendulum-bar to register on, and of means for fixing the pendulumbar against oscillation, and of other novelconstructions and arrangements of the parts of the device, all as hereinafter fully described and claimed.

In the accompanying drawings, illustrating my invention, Figure l represents a front elevation of my improved gravity-level arranged with a suitable frame, the lower part of the pendulumebar being shown in broken lines. Fig. 2 represents a sectional view of the level,

taken on line 2 2 in Fig. 1, and showing the constructions and relative disposition of the several features of invention.

In the said drawings like numbers of reference designate corresponding parts throughout.

Referring to the drawings, the frame 5 may be of any suitable shape to properly support the parts of the device, and is provided with a ilat base, 6, which is supposed to represent the horizontal plane in using the level. The frame 5 is formed with a cylindrical chamber, 7, having an open front. In the center of the back of chamber 7 is arranged the stop-screw 8, provided on the foot with the conical bear ing-socket 9, and working in the screw-threaded perforation l0 of the frame.

The rigid arm l1 is fixed upon the front of Vthe frame by means ot' a set-screw, l2, and eX- tends radially to about the center ofthe opening of the chamber 7, and is provided upon the back thereof with the conical bearingsocket l3,which is adjusted to lie opposite the bearing-socket 9 of the stop-screw 8.

The pendulum-bar 14 is provided near the center thereof` with the fixed pivot I5, set normal to the plane of oscillation of the bar, and provided with the conical ends or journal-cen4 ters 16 and 17, respectively, which are journaled in the bearingsockets I3 and 9, respectively. u v

The lower end of the pendulum -bar 14 is provided with a suitable weight, I8, formed somewhat crescent-shaped, and designed to give sufficient momentum to the bar in oseillating. The upper portion of the pendulumbar, above the pivot 15, is made like an index` hand, I9, and is bent transversely on itself, in order to place the said upper and lower portions of the bar in parallel planes, as clearly indicated in Fig. 2, and the purpose of this construction is to permit the index-hand 19 to lieto the front of, while the weighted end lies -to the back of, the graduated dial 20,which is face with the graduations of the degrees of a circle, beginning with zero at the top and ruuning around each way in graduations of five degrees till ninety degrees are reached at diametrieally-opposite points at the sides, and then beginning with these ninety degree points as zero-points the graduations continue Still uniform until the ninety-degree point is reached at the bottom of the dial, thus completlng the circle and making the requisite sum total of three hundred and sixty degrees.

The dial-plate 20 is loosely set in the cutaway portion or depression 23, and the ringplate 2 4 is placed over it and clamps it securely 1n adjusted position against displacement by means of the screws 25 being socketed in the frame 5. The glass plate 26 is mounted within the ring-plate 24, as shown, and serves to exclude the dirt from the works of the device. By virtue of the construction of the dial 20 being clamped in position by the removable ring-plate 24, the dial may be readily released and trued to the zero-point, and 1n this position may be securely set.

The pivot l5 is peculiarly mounted, as before described, in relation to the stop-screw 8, in order .that the screw may serve to stop and iiX the pivot against movement, and thereby stop the oscillation of the pendulum-bar when 1t 1s desired to set said bar at any point on the dlal. This stop adjustment of the pendulumbar secures the important advantage that when 1t is desired to preserve or Akeep the reading made by the index-hand on the dial the stop-screw 'may be easily turned to rml y h old the indes-hand. In eases where the positions to work in are inconvenient or the under face of a surface is to be leveled, this stop adjustment becomes of great service. The graduatlons of the dial 2O may be changed from the way I show it, and may be arranged to read from zero up to three hundred and sixty degrees 1n consecutive order.

In place of the peculiar form of frame 5 here illustrated, the works of the level may be set 1n a rectangular block, as is the casein spiritlevels, and thereby have four dat surfaces at right angles to each other, and each of which may be used as a plane to work from, in amanner well known. From the foregoing description of my level 1t will be readily seen that the device may be used for all kinds of work in the nding of relatlve angles of lines, or in adjusting a line or plane at an inclination equal to a given inclination; and, moreover, may be readily trued and set.

There may be various modifications made in the principal parts of my invention without, however, making a substantial departure from the spirit of the same, as herein described and claimed.

It is to be observed that by the use of the logarithmic table of tangents, together with the graduations on the dial of the level, and by knowing the lengthof the index-hand, a very slight calculation will give the relative inclination of a given line or surface in terms of the index-hand, since 'such a value will be merely proportional tothe ratio between the said inclined line or surface and the horizontal. For instance, if the index-hand be one inchj long and it registers forty-tive degrees, the ratio of inclination will beone to one, or for one horizontal inch the given inclination will be one vertical inch, and for two inches horizontal the inclination will be two inches vertical, and so on. Thus by an ordinary use of logarithmic tables my level can be used to give Valuable information or data to work on.

It is obviousl y impracticable to put a scale of the tangential values upon the dial; but the calculations may be made from a table, as above described. i

I disclaim, broadly, the use of a gravity pendulum-bar swinging on a pivot set in adjustable bearings and provided with an indexhand moving over a graduated dial, and'having means for setting said bar in a iiXed position, for -I am aware that such constructions l have heretofore been used.

Having thus described my invention, I claim as new and desire to secure by Letters Patenta l. In a gravity-level, the combination of a pendulum-bar provided near the center with a xed pivot set normal to the plane of oscillation and provided with taper ends, a support-frame provided with a base, an arm having a bearing-socket formed thereon for one end of said pivot, a stop-screw formed on the end remote from the head with a bearingsocket for the other end of said pivot, said screw mounted in the frame opposite the bearing-socket in said arm, the pivot journaled in the said bearing-sockets, substantially as described, whereby the stop-screw may be turned to tighten and loosen the play of the pivotjoints, and maybe set to fix the pendulum-bar in any position of its oscillation, for the purpose herein set forth.

2. In a gravity-level, the combination of a IOO suitable support-frame provided with a eylindrical chamber having an open front and a closed back, a stop-screw formed with a conical bearing-socket in the end of its foot and set through the center of the back of said' chamber, a rigid arm extending partially across the front of said chamber and provided on the back with a conical bearing-socket disposed opposite the socket in said stop-screw, a graduated dial placed over the front opening of said chamber and provided with a central eye in alignment with the said bearing-sockets, a pendulum-bar having a pivot near the center, provided with conical ends which are journaled in the said bearing-sockets, respectively, a ring-plate mounted upon said support-frame over the dial and holding the dial in place, and a glass set in said ring-plate, all constructed substantially as and for the purpose described.

3. The combination, with the frame 5, pro- ISO ' vided with the chamber 7., of the arm 11, pro- In Witness whereof I have hereunto set my Io vided with the conical bearing-socket 13, the hand. stop-screw 8, provided with the bearing-socket 9, and set through the Screw-threaded perforation lO, the graduated dial 20, having the centraifeye, 21, therein, the ring-plate 24:,ren1ovably fixed upon the frame, and the glass 26, all constructed and arranged substantially as and for the purpose herein described.

EDVARD DUFFY.

Witnesses:

J. A. MILLER, J r., M. F. BLIGH. 

